After rebuilding my engine i noticed an oil leak and it turned out to be a faulty rear main seal. Once i finished that dreaded job i noticed my car wasnt running right and i thought it was because i needed to do a throttle body relearn. When i did the relearn the car still wasnt running right, but it was running fine before. I noticed my headers were glowing red hot just at idle so i checked for culprits like vacuum leaks and unplugged connections but all seems well. After running for a while the car starts to stall and eventually doesnt turn on anymore (until cold again). At this point im thinking its a timing issue but i still got a tune on my ecu because i can still swap maps and recently redid my timing chain because of the rebuild, so im not too sure.


There are no engine codes active, o2 sensors read lean, maf sensor reads higher than stock because of cams and bigger intake, crank and cam sensors are newish and read fine, fuel pressure is good, throttle body looks like its working fine, oil pressure reads good, doesnt overheat.

 

Do you have cats?

 

no cats

 

Hmm that was my guess, plugged cats.

 

I've seen this happen before on a different car, but I think the principle is the same. Make sure you have your ignition coils plugged in right! I suspect the firing order is messed up and you have unburnt fuel combusting in the headers.

It's not uncommon to see folks mixup coil plugs for cylinders 1 & 3 (passenger side) and I think 4 & 6 or 2 & 4 (driver's side). Something like that. Double check the harness connections, the factory harness is labeled, but more often than not the labels will have flaked off by now. The engine will run like garbage if the coils are switched up.
Cheers!
-Icer